Longer-term forecasting has its up and downs. As many of you know, even forecasting a week in advance can be tough, so how can you expect any meteorologist to have any accuracy in a month-long forecast? First, we have to differentiate a short-term forecast from a long-term forecast. In the short term, we like to give as much insight as we can on overall sensible weather. Parameters like temperature, amount of precip, wind, etc., are given numerical values. These values are usually very accurate going out 5 days or so. Past 5 days, confidence is usually lower, but we still can put numbers on these things. Long-term forecasting, on the other hand, is more abstract. Instead of forecasting exacts, we like to use climatology as a medium to compare to. In other words, long-term forecasting deals with comparing various weather parameters to their averages for the given time of year.
I’m going to focus on the North East alone for this outlook and begin with precipitation. As of November 1st, 51% of the North East is in a moderate drought or worse. Because droughts are a positive feedback cycle (they build upon themselves) and the next 10 days look pretty dry, I believe that November will see less than normal precipitation. This doesn’t mean there wont be some days with heavier rain (or even snow), but overall, November should be relatively dry.
Now onto temperature. There are two models, the American (GFS) and the Canadian (GEM) that are showing some similarities for the rest of this month. The 1st half looks to start out warmer than average, with a possible pattern shift coming around mid-month. Both these models indicate a strong ridge of high pressure dominating the west coast of North America starting next week or so. Because the atmosphere is one fluid system, a ridge in the west can usually mean a trough in the east. This trough is associated with a southward dip in the jet stream, which would allow cold Canadian air to penetrate the North East. If this happens, the temperatures for mid/late November will be closer to average, possibly trending on the cooler side compared to average. But overall, I am expecting November to see slightly above average temperatures, but this really depends on this potential colder pattern that may develop later this month.